The present invention is directed to apparatus for producing high resolution, hard copy images.
Among the innumerable uses to which modern-day computer systems are put is in the generation of graphic output images. These may range from simple x-y plots to perspective representations of three-dimensional forms and surfaces. A particular class of display devices on which such images can be presented is so-called matrix displays. As the name suggests, the images displayed by these devices are made up of a matrix of discrete display points, or sites, which are typically arranged in a row-and-column array. Among the unique characteristics of matrix displays is that each display site can be randomly addressed and its state, e.g., "bright" or "dark," independently specified. Advantageously, this renders matrix displays easily interfaced with and controlled by digital computer circuitry.
Matrix displays are of two general types. Printing, or nonreactive, displays, such as ink jet and electrostatic pin printers, generate hard copy images on a permanent record medium--paper. On the other hand, electronic, or reactive, displays, such as the ac plasma panel, generate nonpermanent images via the selective energization of individual light-emitting or light-absorbing display elements.
In order, for example, to represent fine detail and provide smooth, well-rounded curves in graphic output images, it is necessary for the images to have relatively high resolutions (sites per cm). The images, as generated, may already have such high resolutions. Alternativelly, arrangements have been devised which process an input image having a relatively low resolution to transform it into an output image of higher resolution. Illustrative are the arrangements disclosed in the following U.S. Pat. Nos. 3,921,164 issued Nov. 18, 1975 to B. M. Anderson; 3,604,846 issued Sept. 14, 1971 to D. Behane et al; 3,573,789 issued Apr. 6, 1971 to J. V. Sharp et al. In either case, the ability to display the high resolution image is, of course, dependent on the availability of a high-resolution display device.